DWDT Series Duct Dewpoint Transmitter
Instruction Manual
Duct Dewpoint Transmitter
DWDT Series – Installation Instructions
INTRODUCTION
The duct dewpoint transmitter is designed for use in environmental monitoring
and control systems where high performance and stability are demanded. It’s
state-of-the-art design combines digital linearization and temperature
compensation with a highly accurate and reliable thermoset polymer based
capacitance humidity sensor and curveatched NTC thermistor temperature sensor
for reliability and accuracy in the most critical applications. The sensors
are encapsulated in a 60 micron HDPE filter at the end of a 230 mm (9”) S/S
probe and a compact enclosure.
BEFORE INSTALLATION
Read these instructions carefully before installing and commissioning the
transmitter. Failure to follow these instructions may result in product
damage. Do not use in an explosive or hazardous environment, with combustible
or flammable gases, as a safety or emergency stop device or in any other
application where failure of the product could result in personal injury. Take
electrostatic discharge precautions during installation and do not exceed the
device ratings.
MOUNTING
The transmitter installs directly into any air duct with a minimum
width/diameter of 25.5 cm (10”). Select a suitable installation area in the
middle of the duct wall. To achieve the best reading, do not place in an area
where air stratification may be present. Mount the sensor at least 1.5 m (5 ‘
) in either direction from elbows, dampers, filters or other duct
restrictions. Avoid areas where the transmitter is exposed to vibrations or
rapid temperature changes.
Once a suitable spot is selected, drill a 15 -20 mm (0.6” – .75“ ) hole for
the probe. Slide the probe in the drilled hole until the enclosure is flush
against the duct. The airflow direction is not important. Secure the enclosure
to the duct with (2) #10 x 1” (25 mm) self tapping screws (not provided).
Tighten screws until the enclosure is tight against the duct and that there is
no movement of the enclosure as shown in Figure 1.
A foam gasket is provided on the back of the enclosure that provides a tight
seal against any air leaks. The enclosure has a hinged cover with a latch.
Open the cover by pulling slightly on the latch on the right side of the
enclosure and at the same time pulling on the cover, as illustrated in Figure
2.
A 1/2″ NPT threaded connection hole is provided in the bottom of the enclosure
as shown in Figure 3. Screw the EMT connector or cable gland connector in
until tight. It is recommended that weatherproof conduit or cable gland
fittings be used. The F style enclosure includes 1/2″ NPT to M16 thread
adapter and cable gland fitting.
Two security screws are provided which can be installed to help secure the
cover once settings and wiring connections are complete. See Figure 4.
WIRING
- Deactivate the 24 Vac/dc power supply until all connections are made to the device to prevent electrical shock or equipment damage.
- Follow proper electrostatic discharge (ESD) handling procedures when installing the device or equipment damage may occur.
- Use 22 AWG shielded wiring for all connections and do not locate the device wires in the same conduit with wiring used to supply inductive loads such as motors.
- Make all connections in accordance with national and local codes.
Connect the 24 Vac/dc power supply to the terminals labeled PWR (power) and
COM (common) as shown in Figure 6. This device has a half-wave type power
supply so use caution when wiring multiple devices so that the circuit ground
point is the same on all devices and the controller. The device is reverse
voltage protected and will not operate if connected backwards.
DIMENSIONS
OPERATION
Start-Up Mode
When the device is powered on, it will go through a brief start-up mode. The
LCD will display a sequence of information depending on the model. At the end
of the start-up sequence, normal operation will begin.
STEP 1 LCD Test
All segments lit for 2 seconds
STEP 2 Model
Displays the model type for 2 sec.
(Volt or current depending on model ordered)
STEP 3 Software Version A1.0 for 2 sec
Normal Mode
In normal operation the device:
- reads the temperature and RH sensors
- calculates values for dewpoint, wet bulb and enthalpy
- updates the LCD values
- updates the analog outputs
- monitors the menu key for activity
If the
